Heat pump



July 22,1958 f N1 E. uNDENBLAb 2,844,633 l PUMP l *Filed dan, 4, 1954INVENTOR.

HTORNEY HEAT PUMP Lindenblad, Princeton, N. J., assgnor to Radio nCorporation of America, a corporation of Delaware 1 Application January4, 1954, Serial No. 401,799 7 claims. Y(ci. 13e-4) v gives oft heat.This phenomenon'is known as the Peltier effect. When a ynumber of thesedissimilar rods are alternately arranged, connected serially vand adirect current .passed through them, alternate junctions become cold andhot. When the cold. junctions and the hot junctions are segregated inthermal conducting relationship,

- ay heat pumping thermopile is formed. Heat will be pumped from theabsorbing cold junction side of the thermopile to the heat liberating`hot junction side of the have been space consuming and designed forylimited special applications. lThese structures have not been unifversally adaptable over the broad heat pump application eld'.v .Thisinvention provides a universally adaptable pile in thin panel form.

[The principal object of this invention is to .providea heat pumpingthermopile of compact .thin panel construction.

thermopilewhich is adaptable for use in a wide range of heat pumpingapplications. l

A further object is to provide a thinpanel thermopile construction whichlends itself to economical mass production manufacture. y

Still another object is to provide a heat pumping'thermopile in panelform which may be adapted to space re-` quirements in the eld.

An illustrative example of va thin, panel heat pumping Athermopileresembles a sandwich. The outer layers are formed of sheets ofelectricity insulating but. heat conducting material. A tilling layerbetweenvthe two outer layers is made up of a plugged perforated plate ofelectricity and heat insulating material. Plugs of dissimilarthermoelectric alloys are placed alternately Within the perforations. lThe` ends of the plugs protrude ashort distance from both surfaces ofthe insulating plate. Thinv stripsA of `electricity conducting materialjoin dissimilar plugs iny a series connected electrical circuit. Thisseries circuit arrangement segregates hot junctions on one side of thesandwich and cold junctions on the other side. The sandwich willtherefore absorb heat through one of its outer vconducting layers andgive ofr heat from the opposite side. i

y'Other objects and advantages of the present invention will become-apparent toY those skilled in the art from a reading of the followingspecication in conjunction with thelaccompanying drawing in which: f

United States Pate v tion of the arrows; and

perforated plate-of insulating material; n

Fig. 2 is a plan view of a thin panel thermopile with the upper outerlayer partially removed;

Fig. 3 is a cross-sectional view in elevation of the panel shown in Fig.2 taken along the line 3--3l in the direc- Fig. 4 is a cross-sectionalview in' elevation of a multipanel thermopile made up of a Vnumber ofsingle thin panel thermopiles. p

' In Fig. l, a plate' 10 of insulating material is perforated in anorderly manner by holes 12 passing Vcompletely through the plate. Theperforations are arranged'in horizontal and vertical rows. By insulatingmateri'alis meant, a material which insulates against both heat andelectricity. Plugs of two dissimilar thermoelectric alloys 4 14 and 16are alternately arranged within the perforai tions. The termthermoelectric alloy is used herein to designate a substance which maybe used in a thermo couple to produce the Peltier effect. These plugs,for

n example, may be made of bismuth and antimony. In this alternatearrangement, one plug is bismuth and the ad-` jacent plugs are antimony.Electrical connectors 18 con'- nect the ends of the alternate plugs toform a series circuit progressingV horizontallyacross'each row. Verticalconnectors 20 connect the extrem-ities of the horizontal .2 therefore,be segregated on one side,l for example,.side thermopile. Heat pumpingthermopiles up to the present 25 of the plate 10;. and hot junctions maybe segregated on the other side 26 Vof the plate 10. A

r When a direct current is passed throughthe series con-y necteddissimilar alloys, the junctions on theside ZS bee.

come cold and the junctions between the alloys on the and. economicallymanufactured heat pumping thermoside yZ6 becomehot. The connectingstripsy 18 and 20 conduct heat as Well as electricity. Theytherefore'aid the cold plug junctions in absorbing heat on the cold side25. This yheat is pumped through the plugs-to the hot v ai?. side 26. Atthe hot side 26,l the heat is ygiven 'off tothe Another object is toprovide a thin panel heat pumping l plugs and the junction formingconnectors.

In- Fig. 2 is shown a plan view Vof an insulating panel. with the topinsulating sheet 30 partially'remove'd'. The lower sheet 32 and the topinsulating sheet 30 are made of material which conducts heat but insulatesV with respect to electricity. These enclosing sheathinglayersallow heat to be absorbed, carried through the panel by the"Peltierr effect and given orf. The sheets 30 and 32 may be made, forexample, of beryllium` oxide which Yconducts heat relatively well and iselectrically insulating sheets of f metal withv a `thin insulatingvcoating, suchqfor example as a copper sheet with a iilm of shellac, mayalso be used; The inner perforated insulating plate 34 may, for' eXFample, be made of Micarta or asbestos or a lavjacorr'l-y poundwhichaisinsulating, with respect tor both heatand electricity. Plugs 36andA 38 madeV ofv dissimilar thermoelectricalloys, for example, bismuthand antimonyA are arrangedA alternately within the perforations. scribedbefore in Fig. l, for ease of connection the per,-

Y forations and plugs are arranged in horizontal and rvertical rows.Horizontal strips 40 of electricity andheat conducting material, forexample, copper, connect the, horizontally arranged Y dissimilar plugsconsecutively toy one another. lVertical strips 44 connect thehorizontal rows of plugs in series arrangement through the"pl'ate.'y

Extension strips 42 provide termina-ls for connecting Va`V A2,844,638latenred .Iulyza s As, de-

source of potential (not shown) to the series connected plugs.

This thin panel thermopile illustrated herein resembles a sandwich. Theouter layers are made of heat conducting, electricity insulating,beryllium oxide. The iilling layer or core is made of a perforated sheetof insulating Milcarta having dissimilar bismuth and antimony plugsdisposed within the perforations or studding the sheet.

When an electric current is passed through the series connected circuit,the junctions segregated on one side of plate 34 become hot and thejunctions segregated on the opposite side of the plate 34 become cold.The outer sheets 30 and 32 of beryllium oxide electrically insulate theexposed plug ends and connecting strips. These outer layers or sheets 30and 32 conduct heat. Heat will, therefore, be absorbed by the coldjunctions through one outer sheet and given oi by the hot junctionsthrough the other outer sheet. If the cold junctions are segregatedadjacent sheet 32, heat will be absorbed through sheet 32 and given offby the hot junctions through sheet 30.

A panel of extensive plan area may easily be formed in this manner bymass production methods. The panels may be formed in large slabs whichmay be conveniently rolled. The center insulating layer or core sheetmay be predrilled to receive the alloys. The alloys may be formed oflong bars of thermoelectric material and precut to the predeterminedplug length. They may be cut large enough to protrude through both sidesof the center insulating sheet. The connecting strips 40 and 44, andterminal extension strips 42 may also be mass produced in largequantities. The panels may be made up in standard lengths and widths ina similar manner to well known types of sheet building material.

When constructing an enclosed compartment to be heated or cooled, thesepanels may be utilized to either form or line the walls of thecompartment. Standard lengths and widths may be utilized whereverfeasible. Where standard lengths will not t, the panels may be cut downto conform to the space to be iilled. In cutting the panels to size, theslit must run between the rows of plugs. Markings 46 may be inscribed onthe outer sheets 30 and 32 to indicate the plug locations as a guide inslitting. It may be necessary to supply extra vertical connecting stripsto join the split horizontal rows of thermopile plugs. The connectingstrips may be especially adapted for field connection Work.

When the enclosure is constructed of these panels, the entire wallsurface of the enclosure will act as a heat pump. The direction ofpumping may be easily reversed, if current is sent through in onedirection, with the plugs properly arranged and connected, heat isabsorbed from the atmosphere and material within the enclosure by thecold junctions within the panel. The heat energy will be transmitted bythe Peltier effect to the hot junctions in the opposite side of thepanel. The heat is liberated by the hot junctions to pass oit into theambient or surrounding atmosphere. The heat conducting but electricityinsulating outer sheet collects the heat liberated by the individual hotjunctions and liberates it uniformly over its entire surface. Heat is inthis manner pumped from inside the enclosure through the thin panelwalls and uniformly out into the surrounding atmosphere.

To reverse the heat pumping process, the current is passed through thethermopile in the opposite direction. Heat is then pumped through theouter sheathing into the outer heat absorbing cold junctions. The alloyplugs conduct the heat through the insulating core of the panel into theinner heat liberating hot junctions. The inner heat conducting berylliumoxide sheathing conducts the liberated heat within the enclosure.

In Fig. 4, a multipanel thermopile is constructed of two individual thinpanel thermopile sandwiches 50 and 52. A sheet of Vheat conductiye`material 54, for example 4 copper, is interposed between the twothermopile panels. The individual panels or thermopile sandwiches are ofnonuniform or different heat pumping capacity. Since these illustratedpanels are made with uniform spaced thermopile plugs, a non-uniform heatpumping capacity arrangement is formed of panels having different planareas. In pumping heat from one side of the panel to the other, not onlythe heat from the absorbing side, but also the Joulean losses generatedin passing current through a resistor must be transmitted. In amultipanel arrangement, therefore, the panels from the heat absorbingside to the heat rejecting side must be graduated to increase in heatpumping capacity. The number of junction forming plugs must increase ineach succeeding panel going from the heat absorbing to the heatliberating side. With uniformly studded panels as illustrated in Fig. 4,panels of greater plan area must be utilized to provide more junctionforming plugs. If a panel having more closely spaced plugs is utilizedfor the second or larger panel of the multipanel arrangement, the secondhigher capacity panel may have the same plan area as the first.

These relatively thin panels lend themselves to mass production methods.lf produced in extremely large quantities, they provide a relativelyinexpensive method of thermal conditioning a compartment, a room or evenan entire home. lf utilized within the roof of a building, they mayutilize the heat of the rays of the sun to help heat the home in thewinter. In the summer, the direction of current flow may be reversed tohelp prevent the suns rays from heating the space below.

What is claimed is:

1. A thin panel thermoelectric pile for maintaining a relatively hightemperature gradient across its relatively thin cross-section comprisinga perforated plate of nsulating material, plugs constituted ofdissimilar thermoelectric alloys, dissimilar ones of said plugs beingdisposed alternately within the perforations in the insulated plate toform a plug-studded plate, strips of conducting material, said stripsconnecting adjacent ends of said dissimilar plugs to connect said plugsin a series circuit, and sheets of electricity insulating but heatconducting material thermally and electrically isolated from each othersheathing both sides of said plug studded insulating plate to form theouter walls 0f said panel.

2. A thin panel thermopile sandwich comprising in combination two spacelayers of electricity insulating but heat conducting material and alling layer disposed between said two outer layers, said lling layerbeing comprised of a perforated plate of insulating material studdedwith alternately disposed plugs of dissimilar thermoelectric alloys, theends of said plugs protruding a short distance from both sides of saidplate, and strips of conducting material connecting the protruding endsof different ones of said alternately disposed plugs protruding fromlike sides of said plate in a series electrical circuit, said strips onone side of said plate being in thermal and electrical contact with oneof said layers, said strips on the other side of said plate being inthermal and electrical Contact with the other of said layers.

3. A multipanel thermopile comprised of a plurality of thermopilesandwiches of nonuniform graduated heat pumping capacity wherein eachsandwich is comprised of the combination set forth in claim 2, sheets ofheat conductive material interposed between each sandwich, saidindividual sandwiches being arrangedin the order of heat pumpingcapacity.

4. A thin thermoelectric heat pumping panel comprised of a perforatedplate of insulating material, plugs constituted of dissimilarthermoelectric alloys dissimilar ones of said plugs being disposedalternately within said perforations to stud said insulating plate, theends of said plugs protruding a short distance through both sides ofsaid insulating plate,strips of conducting material connected betweenends of pairs of said dissimilar plugs protruding from like sides ofsaid plate, said strips connecting said plugs in series relationship,and sheets of electricityrinsulating but heat conductingmaterialthermally and electrically isolated from reach other sheathingsaid plug studded insulating plate.

v5. A thin panel thermopile comprised of a perforated plate ofinsulating material, plugs constituted of dissimilar thermoelectricalloys, dissimilar ones of said plugs being disposed alternately withinsaid perforations, the ends of said plugs protruding a short distancethrough both sides of saidinsulating plate, strips of conductingmaterial, said strips connecting said plugs in series relationship, asource of potential, said seriescircuit being connected acrosssaid-source of potential, said connecting strips providing heatabsorbing cold junctions on one side of said insulating plate and heatliberating hot junctions on the other side of said insulating sheet, andsheets of electricity insulating but heat conducting material thermallyand electrically isolated from each other sheathing both sides of saidplate to electrically insulate said hot and cold junctions.

6. A thin panel thermopile structure well adapted for mass production inlarge sheets for cutting to size in the ield 'comprising a perforatedplate of insulating material, plugs constituted of dissimilarthermoelectric alloys, said plugsbeing disposed within the perforationsin the insulated plate to form a plug studded plate, strips ofconducting material, said strips connecting adjacent ends of dissimilarplugs in a series circuit, sheets of electricity insulating but heatconducting material thermally and electrically isolated from each othersheathing both sides of said plate so as to sheath said strips and saidplugs therein, and the outer visible surface'of said sheets being markedto indicate the positions of said'sheathed plugs.

7. A thin panel heat pumping thermopile sandwich comprising twothermally and electrically isolated outer layers of electricityinsulating and heat conducting material and a core separating said twoouter layers disposed therebetween, said core being comprised of aperforated plate of insulating material, plugs constituted of dissimilarthermoelectric alloys disposed Within said perforations, and strips ofconducting material connecting ends of dissimilar plugs in an electricalcircuit, one of said outer layers being in contact With said strips onone side of said core, the other of said outer layers being in contactwith said strips on the other side .of said core.

References Cited in the le of this patent UNITED STATES PATENTS OTHERREFERENCES Electrical Engineering, July 1951, pp. 589-591.

Mellor, I. W.: A Comprehensive Treatise on Inorganic and TheoreticalChemistry, Longmans, Green & Co., London, 1949, vol. IV, pages 221-222.

